Most exoplanets have been discovered via radial velocity studies, which are inherently insensitive to orbital inclination. Interferometric observations will show evidence of a stellar companion if it sufficiently bright, regardless of the inclination. Using the CHARA Array, we observed 22 exoplanet host stars to search for stellar companions in low-inclination orbits that may be masquerading as planetary systems. While no definitive stellar companions were discovered, it was possible to rule out certain secondary spectral types for each exoplanet system observed by studying the errors in the diameter fit to calibrated visibilities and by searching for separated fringe packets.
@article{arxiv.0803.4131,
title = {The Search for Stellar Companions to Exoplanet Host Stars Using the CHARA Array},
author = {Ellyn K. Baines and Harold A. McAlister and Theo A. ten Brummelaar and Nils H. Turner and Judit Sturmann and Laszlo Sturmann and Stephen T. Ridgway},
journal= {arXiv preprint arXiv:0803.4131},
year = {2009}
}